This invention relates to a process for the production of acetaldehyde dimethyl acetal by the catalytic reaction of methanol with carbon monoxide and hydrogen in the presence of nickel and cobalt and compounds of 3-valent phosphorus as well as halogen or halides as promoter.
It is known that acetaldehyde dimethyl acetal, which is used as a starting product for the synthesis of organic oxygen containing compounds, can be obtained by catalytically reacting methanol with carbon monoxide and hydrogen. According to German Pat. No. 897,403, cobalt bromide or iodide is used as catalyst, whereas according to U.S. Pat. No. 2,727,902 quaternary cobalt complexes are used. In both cases, the reaction is carried out at elevated temperature and pressure. However, acetaldehyde dimethyl acetal cannot be economically produced by these methode on account of the long residence times of more than 30 hours which are required. Although, according to German Patent Application No. 2,625,627, acetaldehyde dimethyl acetal is obtained in the presence of cobalt iodide or cobalt acetate using tributyl phosphine as ligand with residence times of less than 5 hours, the selectivities and conversions are relatively poor.